Docking facility and method

ABSTRACT

An inflatable structure is disclosed comprising a plurality of pneumatic chambers which are mechanically attached to a woven metallic fabric surface. A system of cooperating valves and pumps selectively fill the pneumatic chambers with either a gas or another fluid to alter the buoyancy of the assembly. The structure is sunk to the bottom of a ship-berthing area and remains in said position until just prior to the landing of a watercraft, whereupon said structure is caused to be buoyant, raising itself and any explosive devices which might have been secreted in the berthing area.

United States Patent [72] Inventors Robert E. Welch;

Raymond E. Kelly; Russell S. Ward, all of Panama City, Fla. [21] Appl. No. 52,351 [22] Filed July 6, 1970 [45] Patented Jan. 4, 1972 [73] Assignee The United States of America as represented by the Secretary of the Navy [54] DOCKING FACILITY AND METHOD 10 Claims, 7 Drawing Figs.

[52] US. Cl 114/50 [51] Int. Cl 1363c 7/08, B630 7/18 [50] Field of Search 1 14/44, 50, 43.5, 240 C, 240 D, 240 E; 9/13; 43/7, 102

[ 56] References Cited UNITED STATES PATENTS 1,366,749 l/1921 Skrmetti 43/102 2,342,773 2/1944 Wellman 1 14/435 2,549,475 4/1951 Jardim 43/7 2,922,344 l/l960 Meissner 1 14/435 Primary Examiner-Milton Buchler Assistant ExaminerGregory W. OConnor Attorneys-Richard S. Sciascia, Don D. Doty and William T.

Skeer DOCKING FACILITY AND METHOD STATEMENT OF GOVERNMENT INTEREST The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

BACKGROUND OF THE INVENTION This invention relates to a variable buoyancy structure. More particularly, the invention relates to a submersible structure which is buoyed to the surface upon demand. More specifically, but not necessarily by way of limitation, the invention will be described as it pertains to a docking accessory to clear a berthing zone of bottom resting mines.

In riverine and amphibious warfare it is frequently necessary to land supply and combat ships at supply points and beachheads. Frequently, these landing points are only partially secured and infrequently used. Under these circumstances, an enemy swimmer-diver may implant an explosive device in the landing area to detonate beneath, and thereby sink, the next ship using the landing area. As will be readily understood, the sinking of a ship in a landing area, particularly a remote, partially secured beachhead, is a very great loss. Apart from the hazards to operating personnel that accompany such an enemy action, the beachhead sinking interferes with navigation at the landing. At such advanced locations, the sunken ship hull, which generally blocks the channel, cannot be quickly refloated. As a result the shore landing must be moved to another location, an expensive, wasteful, and timeconsuming operation.

In the past, divers have been sent below to reconnoiter the area prior to the landing of each ship. Such an operation was uncertain because the mines are small and often missed in the turbid water of river watercourses. Too, once a mine was located, its removal or detonation in situ was difficult and hazardous to accomplish. Such operations require skilled personnel and a moderately long time for proper execution.

SUMMARY OF THE INVENTION Applicants invention overcomes the difficulties of the prior art by submerging a mesh grid to lie on the bottom. Prior to landing a ship, the grid is caused to be floated to the surface carrying with it mines deposited on the bottom since the grid was last raised. When on the surface, the mines may be removed or detonated on the grid with a minimum of risk or expenditure of manpower. Since the grid extends over the entire berthing area and an adjacent safety zone, the invention has a heretofore unrealizable efiiciency of 100 percent. That is, it is impossible for a planted mine to escape detection, and hence neutralization, when the device of the invention is employed. The operation of the device may be readily performed on short notice and in a limited span of time by shore-based personnel.

Other uses may, of course, suggest themselves to skilled workers in the civil-engineering arts, however the invention will be described as it pertains to its intended use as a countermeasure to marine mines.

With the foregoing remarks in mind it is an object of this invention to provide an improved method and means for mine countermeasures.

A further object of this invention is to provide a method and means to protect a ship-landing site from bottom-resting marine mines.

A further object of this invention is to provide a variable buoyancy stnicture to raise submerged objects from the bottom of a watercourse.

A further object of this invention is the provision of an improved anchorage which may be secured from implantation of marine mines.

A still further object of this invention is a method of landing a watercraft to eliminate the threat thereto of marine mines.

Another object of this invention is a submergible structure to collect and raise bottom-resting objects within a predetermined area of a navigable watercourse while permitting usage of said area for normal use by water vessels.

A further object of this invention is to provide a means to raise mines from the bottom of a watercourse so as to clear an anchorage of clandestinely planted marine mines.

A still further object of this invention is the provision of a portable structure to be used as a component of a riverine anchorage.

Yet another object of this invention is the provision of a structure to remove marine mines from a predetennined area on short notice using a minimum of nondiver personnel.

A further object of the invention is to provide a structure which maybe operated from the shore to clear the bottom of a predetermined area of marine mines.

Other objects and many of the attendant advantages will be readily appreciated as the subject invention becomes better understood by reference to the following detailed description, when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the device of the invention in operation;

FIG. 2 is a sectional view taken along line 2-2 of FIG. 1;

FIG. 3 is an enlarged scale section showing certain constructional details of the invention relating to the securing of the buoyant chambers to the grid;

FIG. 4 is a plan view showing another arrangement for securing the buoyant chambers and grid together;

FIG. 5 is a plan view illustrating one preferred arrangement for securing the anchor lines to the device of the invention;

FIG. 6 is a schematic showing of the pump arrangement used in submerging and buoying the device of the invention; and

FIG. 7 is a sectional view showing a simplified valve arrangement which may be used in the device of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1 and 2, a grid 11 is shown secured against the current of a stream by a plurality of anchors 12. A line 13 secures each anchor 12 to grid 11. The precise number of anchors 12 required depends, naturally, upon the velocity of the stream, and the five shown should be considered illustrative, only. A plurality of ballast tubes 14 are secured to the bottom side of grid 11.

Before considering the manner in which buoyant chambers 14 are attached to grid 11, a discussion of the nature of the grid material is desirable. It is necessary for grid 11 to be somewhat flexible to conform to bottom irregularities and the flextures caused by partial filling and exhausting of the buoyant chambers 14 as the device of the invention is raised and submerged. This flexibility is also useful in supporting bottom mines as they are raised by the device of the invention. This necessary resiliency is obtainable with a variety of structures, but, in the preferred embodiment, a woven wire fabric similar to that used for fencing is used with good effect. Other constructions of flexible material which can be fabricated to retain these properties may be used for grid 11, if desired. Likewise, grid 11 is made of aluminum for weight reduction purposes, but other materials, such as steel, for example, may be used if more convenient. Grid 11 may be painted or made of wire covered with colored vinyl to make its presence difficult to detect.

Likewise, ballast chambers 14 maybe made from a variety of known constructional materials. However, 6 centimeters inside diameter tubing made of polyethylene has proven satisfactory. Such material is readily obtainable, easily transported, and conveniently worked in the field.

Referring to FIG. 3, ballast tube 14 is attached to grid 11 by a U-bolt 15 passing thereabout and extending through plate 16 and grid llQPlate 16 has a contoured saddle 17 to engage and position ballast tube 14 against the lower side of grid 11. U- bolt also passes through plate 18 on the upper side of grid 11, where it is secured so as to hold the component parts together. As an alternative to the aforedescribed U bolt and plate arrangement, ballast tube 14 may be secured to grid 11 by a simple lashing arrangement. In such an alternative fastening arrangement, a rope 19 is passed about ballast tube 14 and threaded through the opening in grid 1 1 the two together. This alternative arrangement is illustrated in FIG. 4.

Lines 13 are attached to grid 11 by means of an arrangement shown in FIG. 5. A bar 21 is threaded within the weave of grid 11 and has an eye 22 extending therefrom. Line 13 is attached to eye 22 by conventional tackle, not shown.

Referring again to FIG. 1, ballast tubes are collected at their shore end into a single manifold 23 which, in turn, is supplied by a feedpipe 24. An air compressor, or pump 25 and a water pump 26 are connected to feedpipe 24. As shown at FIG. 6, valves-27 and 28 connect pumps 25 and 26 to feedpipe 24 for selective individual cooperation therewith. An input pipe 29, which may draw water from the body of water, and an air filter 31 complete the fluid and air supply portion of the system of the invention.

At the outboard end of each ballast tube 11 a check valve 32 is located. Any suitable check valve type may be used for this purpose, and that shown in FIG. 7 may be considered as illustrative only. As shown, valve 32 is inserted within ballast tube 14 and secured thereto by an external clamp 33 which extends thereabout and constrictively holds ballast tube 14 thereto. A ball 34 is held against a valve seat 35 by a spring 36 pressing thereagainst. Pressure in ballast tube 14 supplied by pump 25 or 26 and in excess of that provided by spring 36 causes valve ball 34 to leave seat 35, so as to permit air or waterflow to occur in the direction of the arrow. When on seat 35, ball 34 prevents the influx of water from the stream.

Although the foregoing structural description is sufficient for one versed in the construction arts to make the invention, a more complete understanding of the invention will be ob tained when said structural description is viewed in the light of the preferred mode of operation.

MODE OF OPERATION The device of the invention may be transported to the site of utilization by any conventional means including aircraft. To facilitate handling and storage, grid 11 may be transported in sections to be joined at the utilization site and have the ballast tubes 14 attached thereto. A typical installation might be 35 meters wide and 100 meters long and require several sections of grid 11 to be joined together.

After grid 11 is assembled, ballast tubes are attached thereto at suitable intervals, 15 meters, for example, using either of the attachment techniques shown in FIGS. 3 or 4. Alternatively, a combination of the two techniques may be used. For example, the U-bolt attachment of FIG. 3 may be used at the extremities of each ballast tube 14 and at selected intervals therealong, for example at the section joints of grid 11, and the lashing technique illustrated at FIG. 4 might be used to secure the intermediate portions between U-bolts 15.

Ballast tubes 14 have check valves fitted in one end thereof and the other ends thereof are then joined to manifold 23 by conventional tubing fittings which may include, if desired, valves, not shown, to balance the fluid flow therein.

When the device is assembled and operational connections made to air pump 25 and water pump 26, valve 27 is opened and air pump 25 is operated to fill all of ballast tubes 14 with air. The assembly is then towed into place by surface vessels, shore vessels, shore-based tractor devices, or rotary wing aircraft.

When the assembly is in place, anchor lines 13 are attached to eyes 22 and anchors 12 dropped to secure the device against the action of stream current or tidal currents. The anchors are placed a predetermined distance from grid 11 to allow a minimum lateral displacement during the raising and submerging thereof. Normally, the lateral distance from grid 11 to anchors 12 is at least four times the vertical distance through which the device moves.

To submerge the device, valve 27 is closed, valve 28 is opened, and water pump 26 is caused to pump water through feedpipe 24 to fill manifold 23 and ballast tubes 14. Pump 26 draws water through input pipe 29 which, in turn, may be placed in the stream or body of water in which the device operates. As the water fills ballast tubes 14, the air displaced thereby is forced out check valve 32. As the water fills ballast tubes 14, they become heavier and sink carrying the structure to the bottom.

Particulate matter and bottom debris displaced by the device when it strikes the bottom is quickly concealed by bottom current action. In daylight tests conducted in clear water, the device is very difficult to detect visually shortly after submergence. In turbid water or after nightfall, when mining activities are normally conducted, the device of the invention is virtually impossible to detect. Further, visual detection may be rendered even more difficult when vinyl-coated wire is used to form grid 11, especially if the vinyl is colored in an appropriate camouflage manner to blend with the bottom color of the particular stream.

When a ship is scheduled to use the landing site protected by the invention, valve 28 is closed, valve 27 is opened, and air pump 25 is started. Air is drawn through filter 31 and forced, via feedpipe 24, into manifold 23 by an air pump 25. The air pressure in manifold 23 forces air into ballast tubes 14 displacing the water therein and causes it to exit, via check valve 32. As ballast tubes 14 fill with air, the buoyancy of the device of the invention increases causing it to rise to the surface carrying with it objects, such as mine 37, placed thereon.

When mines raised by the device of the invention are removed or destroyed, the assembly is again flooded, as before, to sink to the bottom and the ship is docked thereover.

It should be obvious that damage done to the device by detonating mines thereon may be easily repaired in the field. Further, should enemy action damage the device, such damage may be easily detected by periodic raising of the device to the surface. The cause of the damage may be easily located and investigated. In addition, periodic raising and lowering of the device serves as a deterrent to swimmer activity in the area and gives false indications of intended use of the landing area.

The foregoing description taken together with the appended claims constitute a disclosure such as to enable a person skilled in the marine-engineering arts and having the benefit of the teachings contained therein to make and use the invention. Further, the structure and methods herein described meets the objects of invention, and generally constitute a meritorious advance in the art unobvious to such a skilled worker not having the benefit of teaching contained herein.

Obviously, other embodiments and modifications of the subject invention will readily come to the mind of one skilled in the art having the benefit of the teaching presented in the foregoing description and the drawings. It is, therefore, to be understood that this invention is not to be limited thereto and that said modifications and embodiments are intended to be included within the scope of the appended claims.

What is claimed is:

l. A method of defending a landing site from marine mines planted therein comprising in combination the steps Off constructing a flexible grid means having the same dimensions as said landing site;

attaching a plurality of ballast chambers to said grid means to extend the length thereof;

terminating one end of each ballast chamber with a check valve means;

joining the other end of each ballast chamber means to a common manifold and supply means;

connecting said manifold and supply means to a source of air under presure so as to inflate said ballast chamber means for the buoyant support of said grid means;

moving said buoyed grid means to its desired operational position;

securing said buoyed grid means in the desired operational location against movement by water currents moving thereabout;

effectively connecting said manifold and supply means to a source of water under pressure so as to displace said air from said ballast chambers via said check valve means and thereby sink said grid means and attached ballast chambers; and

at a predetermined time after the sinking of said grid means and attached ballast chambers, reconnecting said manifold and supply means to said source of air under pressure, so as to effectively expel the water from said ballast chambers and refloat said grid means to thereby carry with it mines placed thereon during the interval of time it was sunk.

2. A method of defending a landing site according to claim 1 wherein said step of securing said buoyed grid comprises the attachment of predeterminately spaced anchors thereto.

3. A method of defending a landing site according to claim I wherein said steps of connecting and reconnecting said manifold means to a source of air under pressure and effectively connecting said manifold means to a source of water comprises the operation of valve installed in said manifold and supply means.

4. A method of defending a landing site according to claim 1 in which said predetermined time at which said reconnection of said manifold and supply means to said source of air under pressure occurs just prior to the landing of a vessel at said landing site.

5. An improved docking facility comprising in combination:

grid means for flexibly covering a predetermined area;

ballast chamber means positioned on one side of said grid means and coextensive therewith for ballasting said grid means and determining the position thereof;

attachment means partially encircling said ballast chamber means and extending through said grid means for the joining thereof into a unitary assembly;

check valve means in one end of said ballast means for permitting the flow of fluid from the interior of said ballast chamber to the exterior thereof while blocking the reverse fluid flow thereof;

manifold means joining individual ones of said ballast chamber means for fluid supply thereto;

air pump means effectively connected to said manifold means for supplying air thereto; water pump means effectively connected to said manifold means for supplying water thereto;

selection means connected between said air pump mean said water pump means, and said manifold means for selecting whether water or air is to be supplied to said manifold means; and

securing means attached to said grid means for determining the location thereof.

6. An improved docking facility according to claim 5 wherein said grid means is formed of woven wire fabric.

7. An improved docking facility according to claim 5 in which said ballast chamber means comprises a plurality of polyethylene tubes.

8. An improved docking facility according to claim 5 in which said selection means comprises a manually operable value means.

9. An improved docking facility according to claim 5 in which said securing means further comprises:

bar means inserted in the weave of said grid means for distributing loading forces applied thereto;

eye means attached to said bar means for providing an attachment point therefor;

anchor means positioned a predetermined distance from said grid means for preventing current movement thereof; and

line means joining said anchor means and said eye means for mooring said grid means in a desired position.

10. An improved docking facility according to claim 9 where said anchor means are placed a distance from said grid at least equal to four times the depth of the water under said grid means. 

1. A method of defending a landing site from marine mines planted therein comprising in combination the steps of: constructing a flexible grid means having the same dimensions as said landing site; attaching a plurality of ballast chambers to said grid means to extend the length thereof; terminating one end of each ballast chamber with a check valve means; joining the other end of each ballast chamber means to a common manifold and supply means; connecting said manifold and supply means to a source of air under pressure so as to inflate said ballast chamber means for the buoyant support of said grid means; moving said buoyed grid means to its desired operational position; securing said buoyed grid means in the desired operational location against movement by water currents moving thereabout; effectively connecting said manifold and supply means to a source of water under pressure so as to displace said air from said ballast chambers via said check valve means and thereby sink said grid means and attached ballast chambers; and at a predetermined time after the sinking of said grid means and attached ballast chambers, reconnecting said manifold and supply means to said source of air under pressure, so as to effectively expell the water from said ballast chambers and refloat said grid means to thereby carry with it mines placed thereon during the interval of time it was sunk.
 2. A method of defending a landing site according to claim 1 wherein said step of securing said buoyed grid comprises the attachment of predeterminedly spaced anchors thereto.
 3. A method of defending a landing site according to claim 1 wherein said steps of connecting and reconnecting said manifold means to a source of air under pressure and effectively connecting said manifold means to a source of water comprises the operation of valve installed in said manifold and supply means.
 4. A method of defending a landing site according to claim 1 in which said predetermined time at which said reconnection of said manifold and supply means to said source of air under pressure occurs just prior to the landing of a vessel at said landing site.
 5. An improved docking facility comprising in combination: grid means for flexibly covering a predetermined area; ballast chamber means positioned on one side of said grid means and coextensive therewith for ballasting said grid means and determining the position thereof; attachment means partially encircling said ballast chamber means and extending through said grid means for the joining thereof into a unitary assembly; check valve means in one end of said ballast means for permitting the flow of fluid from the interior of said ballast chamber to the exterior thereof while blocking the reverse fluid flow thereof; manifold means joining individual ones of said ballast chamber means for fluid supply thereto; air pump means effectively connected to said manifold means for supplying air thereto; water pump means effectively connected to said manifold means for supplying water thereto; selection means connected between said air pump means, said water pump means, and said manifold means for selecting whether water or air is to be supplied to said manifold means; and securing means attached to said grid means for determining the location thereof.
 6. An improved docking facility according to claim 5 wherein said grid means is formed of woven wire fabric.
 7. An improved docking facility according to claim 5 in which said ballast chamber means comprises a plurality of polyethylene tubes.
 8. An improved docking facility according to claim 5 in which said selection means comprises a manually operable value means.
 9. An improved docking facility according to claim 5 in which said securing means further comprises: bar means inserted in the weave of said grid means for distributing loading forces applied thereto; eye means attached to said bar means for providing an attachment point therefor; anchor means positioned a predetermined distance from said grid means for preventing current movement thereof; and line means joining said anchor means and said eye means for mooring said grid means in a desired position.
 10. An improved docking facility according to claim 9 where said anchor means are placed a distance from said grid at least equal to four times the depth of the water under said grid means. 